Mixture of polychloroprene, vinyl chloride polymer, and butadieneacrylonitrile copolymer



Patented Nov. 3, 1953 MIXTURE OF POLYCHLOROPRENE, VINYL CHLORIDE POLYMER, AND BUTADIENE- ACRYLONITRILE COPOLYMER Ralph J. Signer, Chicago, and Keith F. Bea], Park Forest, 111., assignors to The Visking Corporation, Chicago, Ill., a corporation of Virginia No Drawing. Original application January 14,

1947, Serial No. 722,082. Divided and this application June 8, 1950, Serial No. 166,971

14 Claims.

This invention, which is a division of copending application Ser. No. 722,082, filed January 14, 1947, now U. S. Patent No. 2,547,605, relates to resinous compositions and formed structures produced therefrom. More particularly, it relates to a new and improved synthetic resin composition and formed structures produced therefrom.

Many synthetic resins, such as, for example, vinylidene chloride-acrylonitrile copolymer, vinylidene chloride-vinyl chloride copolymer, polychloroprene, 1,3 butadiene-acrylonitrile copolymer, Vinyl chloride-vinyl acetate copolymer, vinyl chloride-acrylonitrile copolymer, polyvinylidene chloride, etc. are currently and commercially available. A film produced from any of the aforementioned synthetic resins does not possess the necessary properties of flexibility, high resistance to tear, high elongation, capacity to return after elongation, high tensile strength, high resistance to moisture vapor penetration and to penetration by gases, as are required for the packaging of foodstuffs. Attempts were made to improve the physical properties of such films by the incorporation of a liquid plasticizer in the composition from which the films are produced. However, films containing a liquid plasticizer are unsatisfactory for the reason that such liquid plasticizers migrate from the resin or disappear by evaporation, leaving the resin embrittled, and frequently contaminate the contents of the package especially if the contents of the package is a foodstuff.

In the course of research to improve the properties of films produced from synthetic resins mentioned, attempts were made to prepare films of resinous compositions containing a plurality of synthetic resins. However, when attempts were made to form a resinous composition of polychloroprene with vinyl chloride-vinyl acetate copolymer it was found that such resins were incompatible or incompatible in proportions which are necessary to give the desired results.

An object of this invention is to make a plurality of resins, which are normally incompatible in desired proportions, compatible.

Another object of this invention is to provide a resinous composition containing a plurality of resins normally incompatible in the desired proportions and a blending agent which will make such resins compatible.

An additional object of this invention is to provide formed structures formed of normally incompatible resins but which are compatible in the structure.

A further object of this invention is to provide resinous formed structures having improved physical properties.

A specific object of this invention is to provide films formed of resinous compositions having physical properties which render them suitable for use as a packaging material.

Other and additional objects will become apparent hereinafter.

The above objects are accomplished, in general, by incorporating in a resinous composition, containing a plurality of synthetic resins in proportions at which such resins are normally incompatible but which are necessary to obtain the desired properties, a blending agent whereby a homogeneous resinous composition is obtained from which the desired formed structure is prepared and in which structure the synthetic resins are compatible.

The blending agent, in general, is a synthetic resin as will hereinafter be more fully explained.

Usually, the synthetic resin components and the blending agent are dissolved in a solvent or solvent mixture whereby a homogeneous solution is obtained. Herein the term solven covers a single solvent or a solvent mixture. No precise sequence for dissolving the resins and blending agent in the solvent is required. The resin components and blending agent can be added separately or simultaneously to the solvent. After the desired solution has been prepared, it is processed depending on the desired formed structure. In one embodiment of the invention, the resinous composition is formed into the desired formed structure and the solvent evaporated therefrom. In another embodiment, the resinous composition is extruded or cast into a precipitating bath, in which the resins are insoluble and with which the solvent is miscible, and thereafter the precipitated resinous article dried.

The nature of the invention will become more apparent by reference to the examples hereinafter set forth, wherein the proportions are by weight. It is to be understood that the examples are merely illustrative embodiments of the invention and that the scope of the invention is not restricted thereto. For convenience, the specific synthetic resins and specific blending agents of the examples are designated by their respective trade names, the identity of which is set forth in the following table:

E. I. du Pont de Nemours & C0.

55% butadicne.

Hycar OR15 B. F. Goodrich Co..-

457 acrylonitrile. Vmylite VYNS... Carbide & Carbon Chem- {88% vinyl chloride.

c Corp. 12% vinyl acetate. Geon 102 B. F. Goodrich O0 vinyl chloride.

XAMPLE 1 l5 parts Neoprene CG, '15 -parts- Hycar'=OR-15,

and 30 parts Vinylite VYNS were dissolved in a solvent mixture composed of 1'74 parts acetone and 228 parts dioxane Th e resimsolutiontwas cast in thin films onto glass platesiand the solvent evaporated in air at 50 C. The dried-gfilmsgwere stripped from the plates and consisted of 25% Vinylite V'YNS. EXAMPLE 2 from-thisresin solution by -the-method set'iorth in -Example if. The -drid films consisted of-=70% .Neoprene' CG, "';20%= Vinylite -VYNS= and 10% :Hyean ORr15.

EXAMPLE 4 12 parts Neoprene CG, 42 partsrVinylite YYNS,

.. and .6 parts, Hyear,,.OR-15.,wer.e.. dissolved in a ,solvnt,mixture cpmposed of .174 parts. acetone nd 8.11e t diora a; were prepared fro resin-solut n bmmetme et-fo h i xamp,1e llj; The.drie'djlmsconsisted or 20% 'lA-BLE II 1 Thysicalproperties el fllm .,-,Mois- 'm-Tear Example Tensile Elon- {Swen I 1 Film ture. Oxyge 1. gth stir ift? reams 322$ sq.i n. cent v (mils? 'jslilghl sion 322 262:;11L68 4.43 i; 28.7 168 e 9 4,1431 3.76 19.2 322 262 1.68 4.43 9.7

1 Moisture vapor transmission-grams water per 24 hours per 100 square inches.

1 Cubic centimeters gas per 24 hours per 100 square inches. cTesting, methods used in determining values for Table II Tensile Strength.-Seott Inclined -Plane Tensile Strength Tester. Asample 1' inch long by winch-wide is used., .'1 ensilestrength aSr uSed in. {Table II is given in pounds per-squareiinch based on original cross seetion area of the sample. Elongation.'-Determined on same machine and sample as tensile. strength.

Films were-prepared 4 .Teaz: strength.-Thwing-Albert Research Type Tearing Tester. Ant initiated tear, through a 1 inch length of film is used. Tear strength is recorded in grams per inch film thickness. Moisture vapor transmission.-Determined by General --Foods -Method as described in Modern 'Packaging;,f-November 1942. Transmission given in grams of Water passing through an area of elee-square inches of film in 24 hours. 10 2 Oxygen; transmission.Determined by method sand.apparatus-described in Paper Trade Jour- ,nal 113 No. 10, 32 (1944). Transmission recorded asi'cubic: centimeters of gas passing through an-area ,of-lOO square inches of film in 24 hours. No special method of preparing the solution of the synthetic resins and blending agent is necessary. The components can be added either ,zszs'separately or simultaneously to theseleeted solw ventrtIhemass is preferably agitated-"until tsolution .is zeomplete. The solution"'can'also be facilitated; and. shastened by thel appl'ic'ation of e -;--heat.

11,-. As shown by-the examples th'e solution 'can be extruded. and the. solvent 1 evaporated thereirom, for the solutionscan be extruded intoi-abath which is i a. precipitating Iagent for the resins .and-f pref erably' also .is- :miscible' .with 'the'fsolvent of: the 1 :r-composition.

The solvents which :can be emplo'ye'd m the 3.0 1 production of i shaped articles from -the" solution are.inot iestricted to those of' the -e'xamples. When;v for =examp1e, anarticle is to be-=prepared 1 bysthe process wherein thesolventis evaporated, azany'volatile solvent in -whiehi all of the i'sins 5 aresolubleLcan beused? Vl/'hen-- the"-' article is to be prepared by a' method -wherein the solu- 'tion is extruded into a preeip'itating bathjeny solvent in which all the resins: are-*sblubla and :which preferably: also is miscible' with the-pre- 40 :cipitating 'bath; can= be usedl' Genrallyi such wisolvent is-lvolatile so that, upon-drying of the 7-: article, the: residual solvent will be *evaporated. In the embodiment of the inventiomwherein the solution is extruded into a precipitating bath, 4 7;. -the' latter is a liquid medium-,lwhich precipitates theresin-fromthe solutioni 'The' precipitating 1 :bath is also on'e which in admiXture 'With the 1 ?so1vent will form a mixture which is anonsolvent for the resin. Though many liquid -substances and solutions can beu'sed as '-the-precipi- 'tatin'g bath, water is"preferred"=beeause of its economy. The total resin concentration in the solution is not restricted to those set forth in the-examples. In general, when the'solution is to be processed by a' procedure wherein the solvent is evaporated from th'e shaped article, the tOta-"i i'esiri-(including; blendmgagent) can "vary within" limits. Usually, a total resin concentration OI",10% to -30%; and preferably about 15% .isju sed.

For wet casting operations, i. e.',when, the solution is extruded .into aprecipitatin'g' bath, asolution'viscosity of. 10 to 25. seconds by. the falling. ball. method desired} .(this .represents ".Fthe--.time,.;required.for a.- 1/3=L' steel ball to,- fall vertically through 8". ofthearesinrsolution). Asolidscontent of approximately- 15% to 25% is required to :give. such a viscosity. t .-.1nstead of blending through the use of-solvents, the various latices can be mixediandthereafter -coagulated,-,.:and sub,sequently qheated l and/or N. .milled.

The films produced by this inventionnare trans- =parent and 'can be-unvuleanized oruvulcanized,

as desired. In general, when a vulcanized film is desired, the composition can contain any filler, reinforcing pigment, age resistors, accelerators, and vulcanizing ingredients which are ordinarily used in vulcanizing rubber or synthetic rubber. When such a composition is used, the film, after or during drying, can be vulcanized in the known manner. By the appropriate selection of the vulcanizing agents, one or all of the vulcanizable constituents can be vulcanized to itself or to each other. vulcanization of a specific constituent depends on the concentration of such ingredient and the use of the vulcanizing agent which will vulcanize only such ingredient.

Various other substances may be included in the formula, such as softening agents, plasticizers, etc., although in general these may not be desirable.

Furthermore, anti-blocking materials, such as parafiin, stearamide, natural waxes, synthetic waxes, stearic acid, cetyl acetamide, ethylene bis palmityl amide, dicetyl ether and their homologues, may be incorporated to improve the surface properties.

As is disclosed in Examples 1-4 inclusive, resinous mixtures of polychloroprene and vinyl chloride-vinyl acetate copolymer are made compatible by the addition of a blending agent consisting of butadiene-acrylonitrile copolymer.

Though in Examples 1-4 inclusive, a vinyl chloride-vinyl acetate copolymer containing 88% vinyl chloride is used, vinyl chloride previously polymerized alone (see Example 5) or copolymerized with vinyl acetate to give a copolymer containing up to 18% vinyl acetae can be used.

In the examples, the blending agent is 1,3 butadiene-acrylonitrile copolymer (45% acrylonitrile). However, the blending agent is not restricted to such butadiene-acrylonitrile copolymer. In general, 1,3 butadiene-acrylonitrile copolymer containing from 25% to 45% acrylonitrile can be used as the blending agent.

In general, the butadiene-acrylonitrile blending agent can be used in amounts of from to 25% by weight of the total resins.

The polychloroprene and the vinyl chloridevinyl acetate copolymer can vary within limits. In general, the composition can contain to 70% polychloroprene and 70% to 20% of vinyl chloride-vinyl acetate copolymer.

Various solvents are disclosed in Examples 1-5 inclusive, but it is to be understood that the invention is not restricted thereto. Any solvent, as hereinbefore described, can be used. In addition to those set forth in the examples, other illustrative solvents for solutions to be processed by the evaporative method are tetrahydrofuran, dioxane, isophorone, higher ketones such as methyl isobutyl ketone, cyclohexanone, etc., a mixture containing 62% acetone and 38% dioxane, and preferably a mixture containing 85% to 75% acetone and 15% to tetrahydrofuran. Methyl ethyl ketone can be substituted for acetone in a somewhat higher proportion than acetone.

The above-mentioned solvents can be used in wet extrusion processes wherein water constitutes the precipitating bath.

Though the invention has been previously described particularly in connection with the production of film, it is to be understood that the invention is not restricted thereto. The solutions also can be used for the preparation of self-sustaining continuous film in the form of continuous seamless tubing. Likewise, the solutions hereinbefore described can be used in the production of other shaped structures, such as filaments, yarns, fibers, caps, bands, etc. Additionally, the solutions can be employed as a coating composition for the coating of various base materials, such as paper, fabric, metalfoil, regenerated cellulose, polyvinyl alcohol, nylon, zein, ethyl cellulose, cellulose acetate, etc. Still further, the solutions can be used as a sealing cement for gasproof seals of resinous sheet materials, as a cement for sealing films of polyvinylidene chloride and its copolymers, as a gasket cement, etc.

Self-sustaining film in the form of continuous sheeting or seamless tubing produced from the components of synthetic resins, herein described, are characterized by high resistance to moisture vapor penetration and to penetration by gases. Because of these properties, a film of the synthetic resins hereinbefore described is admirably suited for use in wrapping and packaging of any product which is desired to be protected.

In addition to the foregoing properties, a film of the synthetic resins hereinbefore described is transparent, thermoplastic, heat-sealable, resil ient, has a high tensile strength, has a fair amount of elongation, is printable, contains no substance which will affect the odor and taste of the product wrapped therein or will migrate from the film into the product wrapped therein, resists exudation of fatty substances, and is highly resistant to puncture, all of which properties render the material particularly suitable for packaging or wrapping of foodstuffs.

Herein and in the claims the proportions are by weight unless otherwise specified.

In the claims, the term consisting essentially of is intended to cover the named ingredients with or without the modifying ingredients herein disclosed.

Since it is obvious that various changes and modifications may be made in the above description without departing from thenature or spirit thereof, this invention is not restricted thereto except as set forth in the appended claims.

We claim:

1. Formed structures consisting essentially of 20%-70% polychloroprene and %-20% of a I 3 vinyl polymer selected from the class consisting of polyvinyl chloride and copolymer of 88%- 82% vinyl chloride and 12%-18% vinyl acetate, said polychloroprene and vinyl polymer being normally incompatible, and 10%-25% of a synthetic resin blending agent consisting of a rubbery copolymer of %-55% of 1,3 butadiene and 25 %-45% acrylonitrile whereby said incompatible polychloroprene and vinyl polymer are made compatible.

2. Formed structures consisting essentially of 20%-70% polychloroprene and 70%-20% polyvinyl chloride, said polychloroprene and polyvinyl chloride being normally incompatible, and 10%-25% of a synthetic resin blending agent consisting of a rubbery copolymer of 75%55% of 1,3 butadiene and 25%-45% acrylonitrile whereby said incompatible polychloroprene and polyvinyl chloride are made compatible.

3. Formed structures consisting essentially of 20%-70% polychloroprene, 70%-20% of a vinyl chloride-vinyl acetate copolymer of 12%-18% vinyl acetate and 88%-82% of vinyl chloride, and 10 %-25 of a synthetic resin blending agent consisting of a rubbery copolymer of 75%55% of 1,3 butadiene and 25%-45% acrylonitrile aezssgoco' 7, wherebyu'said polychloroprene? and vinyl chloride' vinyl acetate copolymer being normally incompatible arecmade compatible? 4z-Fomed structuresfas set forth. in claiml wherein the'wblending agent 'is a rubbery co-' polynieriof 55% of 1,3 butadiene': and '45%"acrylonitrilei 5lhFormed 'structures -ais'setiforth in claim 2 wherein the" blending agent is a'rubbery copolymertof: 55%10? 1;3bi1tadiene. and '45 acrylonitrilec 6: Eormed structures as set forth in claim 3 wherein the blending agent is. a rubbery" copoly-men of 55 of" 1,3 butadienevand 45 acrylonitrilez 7.- self-sustainingifilm consisting essentially of a." mixture; of '70%-20% 'polychloroprene and 20%'-'70% of F a; vinyl :Ipolymer selected :from i the class consistingaof polyvinyl chloride' andcopolymer: of188% -82 vinyl chloride and 12%- 18% vinyl acetate; said polychloroprene and vinyl polymer 'beingnormally incompatible, and %-25%i'of a' synthetic' resin blending agent consistingtof a rubberycopolymer of 75%-55%' of? 1,3 ibutadienewandw 25%-45% acrylonitrile whereby: saidincompatible polychloroprene and vinylipolymer are made compatible.

8: Selfsustaining film consisting essentially of az'tmixture' of 70'%- 20% polychloroprene and 20% 7070': of polyvinyl chloride, said polychloroprenea and-polyvinyl chloride being normally incompatible,:and" 10%'-25% of a synthetic resin blendihg'2ragent':consisting of a rubbery copolymer of 75%-55-%: butadiene -and '25%-45%'acrylonitrile:wherebyesaid incompatible polychloroprene and polyvinyl chlorideare made compatibleml 9; Self=sustaining :film': consisting essentially of a ;mixture'of '7 0 %"-20 polychloroprene and 20%-70% of a vinyl chloride-vinyl acetate" 00-' polymer .containingi 12 -18 vinyl acetate-and 88%-82%; vinyl ichloride, said polychloroprene and copolymer being normally-incompatible, and 10%:-25% of a synthetic resin blending agent consisting of a rubbery copo1ymer'of '75% 55% butadiene and 25%-45% acrylonitrile whereby sisting; of a rubbery copolymerof 55% of 1,3

butadierieand 45% acrylonitrileto make said .chloride-vinylacetate vinyl acetate; and 10% ofra blending 'agent'con sisting of a rubbery'copolymer of 55%"of 1,3 butadiene and 45%acryl0nitri1e' to makesa'id' chloroprcne and" vinyl chloride-vinyl acetatecopolymer compatible.

13. Self-sustaining transparent film consisting essentially of polyc'hloroprene, 20% ofi a copolymer of' 88% vinyl chloride and=12%" vinyl'acetate, and 10% of a blendingagent con-" Sisting' of a rubbery="copolyme1'= of 55% of 1,3" butadiene and 45% acrylonitrile'to make said chloroprene and vinyl chloride-vinyl "acetate copolymer compatible.

14. Self-sustaining transparent film consis't'-- ing essentially of'40% polychloropren'e; '50%'= polyvinyl ch1oride'and"10%-of ablendin'g agent consisting of a rubbery copolymer of 55%' of'1,3 butadiene' and 45% acrylonitrile to' makesaid chloroprene and polyvinyl chloride compatible? RALPH J. SIGNER: KEITH F; IBEAIILA M References Cited the file of tliimatent UNITED STATES PATENTS Number Name Date 2,247,154 Geiger'etal; June24yl94l- 2,278,833 Crawford; Apr: 17,- 1942- 2,319,959: Turneyu; May 25; 1943 2,330,353 Henderson; Sept: 28, 1943 2,445,727 Kinzingeri Ju1y-'20',1948= 2,459,874 Fay .Jan'.' 25,--1'949 2,552,904 Newberg et'a-l'. May' l5, ll

FOREIGN PATENTS Number country" Date 577,860 Great Britain" June l', 1946 OTHER REFERENCES Garvey et' al., Ind., and Eng. Chem'., 36-'Mar; 1944=pp. 209-211. 

1. FORMED STRUCTURES CONSISTING ESSENTIALLY OF 20%-70% POLYCHLOROPRENE AND 70%-20% OF A VINYL POLYMER SELECTED FROM THE CLASS CONSISTING OF POLYVINYL CHLORIDE AND COPOLYMER OF 88%82% VINYL CHLORIDE AND 12%-18% VINYL ACETATE, SAID POLYCHLOROPRENE AND VINYL POLYMER BEING NORMALLY INCOMPATIBLE, AND 10%-25% OF A SYNTHETIC RESIN BLENDING AGENT CONSISTING OF A RUBBERY COPOLYMER OF 75%-55% OF 1,3 BUTADIENE AND 25%-45% ACRYLONITRILE WHEREBY SAID INCOMPATIBLE POLYCHLOROPRENE AND VINYL POLYMER ARE MADE COMPATIBLE. 